Lengths of corrugated metal pipe are commonly coupled together end-to-end by means of an external circumferential coupling band which is drawn tightly around adjacent pipe ends and fastened in place by suitable connectors at opposite ends of the band. Circumferential seals may be provided between the respective pipe ends and the coupling band.
Various systems, commonly employing bolt and nut-type connectors, have been proposed for tightening and fastening the bands in place. For example, U.S. Pat. No. 3,501,179 shows helically corrugated pipe sections with ends which are recorrugated strictly circumferentially and which are joined together by a circumferential coupling band which is itself corrugated to complement the corrugations on the ends of the respective pipe lengths. The opposite ends of the band are drawn tightly together and fastened around the pipe ends by adjustable fasteners comprising bolt and nut assemblies connected between fittings at the respective ends of the band. In order to tighten and fasten the band around the pipe ends, the bolts and nuts must be inserted in the respective fittings and drawn tight by means of a wrench or the like.
There have been numerous other proposals for coupling band fastener systems, but generally these tend to be somewhat complex, difficult to apply and release, particularly in situ, and difficult to tighten to precisely the optimum degree of tension.